Marine ecosystems are strongly impacted by the consequences of human activities, such as habitat destruction or artificialization and climate change. In the Mediterranean Sea, sessile benthic species, and particularly octocorals, have been affected by mass mortality events linked with positive thermal anomalies. The future survival of octocoral populations impacted by global change will depend on their recolonization abilities facing local extirpation or important modification of their habitat. We studied these processes in Mediterranean octocorals in two situations: the colonization of artificial substrates (wrecks) by the red gorgonian Paramuricea clavata , and the recolonization following mortality events in the yellow gorgonian Eunicella cavolini . With microsatellite markers (seven for P. clavata , five for E. cavolini ), we analyzed the genetic diversity of populations on artificial substrates and their differentiation from other neighboring populations. For P. clavata the populations on artificial substrates were not or lowly differentiated from the closest populations (1.3–1.6 km) on natural substrates, and showed similar levels of genetic diversity. Artificial substrates can then be considered as an interesting substitute for natural substrates for this species. For E. cavolini we did not detect any variation in diversity or relatedness following recuperation after mortality events. In both cases, our results suggest the input from different populations in the recolonization process, which helps in maintaining the genetic diversity. These results are useful for the management of these species and of associated ecosystems.

中文翻译：

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对地中海八珊瑚重新定殖过程的遗传见解

海洋生态系统受到人类活动后果的强烈影响，例如栖息地破坏或人工化和气候变化。在地中海，无柄底栖物种，尤其是八珊瑚，受到与正热异常相关的大规模死亡事件的影响。受全球变化影响的八珊瑚种群的未来生存将取决于它们面临局部灭绝或栖息地重大改变的重新定殖能力。我们在两种情况下研究了地中海八珊瑚的这些过程：红色柳珊瑚 Paramuricea clavata 对人工基质（残骸）的定殖，以及黄色柳珊瑚 Eunicella cavolini 死亡事件后的重新定植。使用微卫星标记（P. clavata 7 个，E. cavolini 5 个），我们分析了人工基质上种群的遗传多样性及其与其他邻近种群的差异。对于 P. clavata，人工基质上的种群与天然基质上最近的种群（1.3-1.6 公里）没有差异或差异很小，并且显示出相似的遗传多样性水平。然后可以将人造基质视为该物种天然基质的有趣替代品。对于 E. cavolini，在死亡事件后恢复后，我们没有检测到多样性或相关性的任何变化。在这两种情况下，我们的结果表明在重新定植过程中来自不同种群的输入，这有助于维持遗传多样性。这些结果对管理这些物种和相关生态系统很有用。